• Animal Systematics, Evolution and Diversity
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• 제39권4호
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• pp.264-271
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• 2023

The edible jellyfish Rhopilema esculentum occurs in waters throughout northeastern Asia, including in Korea, China, and Japan. In Korean waters, R. esculentum has appeared in two regions (Gangwha and Muan). Based on the appearance of young medusae and coastal distribution records, these two regions may be key R. esculentum breeding sites. In the present study, we investigate and compare the genetic structure of R. esculentum in the two regions using mitochondrial sequences (16S ribosomal RNA and cytochrome c oxidase subunit I). The genetic diversity of the R. esculentum population at Ganghwa exceeded that of the population at Muan. Despite considerable geographic separation (400 km) between the two regions(Gangwha and Muan), our haplotype network suggests that the Gangwha and Muan populations of R. esculentum are related. The simple and monotonous genetic structure of the Muan population shows that R. esculentum emergence is relatively recent. In contrast, the Gangwha population shows evolution. Moreover, jellyfish of the Gangwha population are genetically diverse and remain constant despite environmental fluctuations in the Han River. The Gangwha area is considered to be the old origin of R. esculentum in Korea.

• 한국작물학회지
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• 제48권2호
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• pp.96-102
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• 2003

This study was conducted to determine the effects of two plant populations (28 and 14 plants per $m^2$) and two toppings in conventional plant population (28 plants per $m^2$) on soybean (Glycine max L. cv. Pungsannamulkong) cultivated in the paddy field. The two topping time were taken at 6$^{th}$ to 7$^{th}$ and 8$^{th}$ to 9$^{th}$ trifoliolate leaf stages in the conventional plant population. Experimental design for growth data was a randomized complete block with three replications, and samples were taken at R1 (July 31), R3 (August 19), R5 (September 2) and R7 (September 23) growth stages. The branch number of soybean was relatively higher in the low plant population (14 plants per $m^2$) and with the topping at the 6$^{th}$ to 7$^{th}$ leaf stage, in the conventional plant population (28 plants per $m^2$), and with topping at the 8$^{th}$ to 9$^{th}$ trifoliolate leaf stage in descending order. The highest average branch length of soybean was observed in the low population and the longest branch length was observed from the soybean with topping at the 6$^{th}$ to 7$^{th}$ leaf stage. The leaf number per plant was decreased in order of in the low population, with the topping at 6$^{th}$ to 7$^{th}$ trifoliolate leaf stage, with the topping at 8$^{th}$ to 9$^{th}$ trifoliolate leaf stage, and in the conventional population. The leaf area was high in the low population and with topping at 6$^{th}$ to 7$^{th}$ trifoliolate leaf stage and was relatively low in the conventional population and with the topping at 8$^{th}$ to 9$^{th}$ trifoliolate leaf stage in soybean. The dry weight of leaves and branches was high in the low population and with the topping at 6$^{th}$ to 7$^{th}$ trifoliolate leaf stage and was relatively low in the conventional population and with topping at 8$^{th}$ to 9$^{th}$ trifoliolate leaf stage. The leaf number per plant was high in the low population and with topping at 6$^{th}$ to 7$^{th}$ trifoliolate leaf stage and was relatively low in the conventional population and with topping at 8$^{th}$ to 9$^{th}$ trifoliolate leaf stage. The grain yield per 10a was high with the topping at 6$^{th}$ to 7$^{th}$ trifoliolate leaf stage.

• 대한한의학회지
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• 제32권5호
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• pp.41-49
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• 2011

Objectives: To optimize the preservation method of herbal decoction, we investigated the content of principle components of Pyungwi-san, liquiritin, glycyrrhizin, and hesperidin according to preservation temperature and period. We also investigated the changing patterns of pH and microbial population in Pyungwi-san decoction as a model case. Methods: With samples preserved at different temperatures, the content of liquiritin, glycyrrhizin, and hesperidin was determined using HPLC and microbial population was determined as viable counting method up to 8 times every month. Identification of isolated bacteria was performed by 16S rDNA analysis. Results: The content of liquiritin and glycyrrhizin did not change according to the preservation temperature and period, but that of hesperidin was severely decreased at room temperature. The isolate from the decoction was identified as Bacillus licheniformis by 16S rDNA sequence analysis. Microbial population appeared after 3 months' preservation and reached maximum value at 4 months; at all tested temperatures, the pH showed the lowest value (4.4-4.5) simultaneously. Conclusion: From the results, it seems to be that the microbial growth affects the pH of preserved decoction but not the change of liquiritin and glycyrrhizin content.

• Journal of Animal Science and Technology
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• 제56권8호
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• pp.28.1-28.6
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• 2014

This study was conducted to estimate the effective population size using SNPs data of 240 Jeju horses that had raced at the Jeju racing park. Of the total 61,746 genotyped autosomal SNPs, 17,320 (28.1%) SNPs (missing genotype rate of >10%, minor allele frequency of <0.05 and Hardy-Weinberg equilibrium test P-value of < $10^{-6}$) were excluded after quality control processes. SNPs on the X and Y chromosomes and genotyped individuals with missing genotype rate over 10% were also excluded, and finally, 44,426 (71.9%) SNPs were selected and used for the analysis. The measures of the LD, square of correlation coefficient ($r^2$) between SNP pairs, were calculated for each allele and the effective population size was determined based on $r^2$ measures. The polymorphism information contents (PIC) and expected heterozygosity (HE) were 0.27 and 0.34, respectively. In LD, the most rapid decline was observed over the first 1 Mb. But $r^2$ decreased more slowly with increasing distance and was constant after 2 Mb of distance and the decline was almost linear with log-transformed distance. The average $r^2$ between adjacent SNP pairs ranged from 0.20 to 0.31 in each chromosome and whole average was 0.26, while the whole average $r^2$ between all SNP pairs was 0.02. We observed an initial pattern of decreasing $N_e$ and estimated values were closer to 41 at 1 ~ 5 generations ago. The effective population size (41 heads) estimated in this study seems to be large considering Jeju horse's population size (about 2,000 heads), but it should be interpreted with caution because of the technical limitations of the methods and sample size.

• 한국초지조사료학회지
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• 제37권1호
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• pp.35-43
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• 2017

본 연구는 반추동물이 볏짚을 소화하는 과정 중에 주요 섬유소 분해 박테리아의 분포 변화를 연구하여 반추위내 볏짚이용효율을 증진시키기 위한 진보적 연구 자료를 제공하고자 실시하였다. 본 연구를 수행하기 위하여 분쇄 볏짚을 기질로 사용한 In vitro 반추위 발효를 실시하였으며, 배양 0. 4, 8, 12, 48시간에 볏짚 건물 소화율 및 섬유소 분해 박테리아 균수 변화를 조사하였다. 섬유소 분해 박테리아 균수는 F. succinogenes. R. albus와 R. flavefaciens를 대상으로 Quantitative real-time PCR을 이용하여 16S rDNA의 copy No의 log값(Log copy No)을 측정하였다. 섬유소 분해 박테리아의 총 균수는 F. succinogenes, R. albus와 R. flavefaciens의 볏짚 표면 부착 및 배양액내 부유 박테리아의 총합으로 배양 시간에 따라 증식을 하여 24시간에서 최고 군집(29.0 Log copy No)을 형성하고, 이후 감소하였다. 이에 볏짚 소화율도 24시간까지 점점 큰 폭으로 증가하였고, 이후에는 점점 둔화되는 경향을 나타냈다. F. succinogenes, R. flavefaciens 및 R. albus는 배양 시작 즉시 볏짚 표면에 부착이 발생됨을 발견하였으며, 이때 이들의 부착 군집의 비율은 각각 34.5%, 84.4% 및 67.9%로 차지하였다. 그리고 이들 섬유소 분해 박테리아의 볏짚 부착 비율은 모든 균수가 공히 배양 4시간째부터 94.7% 이상 최고 수준에 이르렀고, 부착 균수는 균종에 따라 각각 배양 12시간 또는 24시간째에 최고 수준을 나타냈다. F. succinogenes, R. flavefaciens 및 R. albus의 최고 수준의 볏짚 표면 부착 속도는 배양 12시간에 시작되어 배양 24시간에 각각 10.33, 9.28 및 8.30 Log copy No/h/g DM에 도달하였다. 그리고 섬유소 분해 속도는 표면 부착 속도보다 좀 늦은 배양 24시간에 0.95% DM/h로 최고 정점에 도달하였다. 따라서 본 연구결과는 반추위 발효 진행 과정에서 섬유소 분해 박테리아 총균의 증식에 따라 조사료의 소화가 증가되며, 상당히 많은 섬유소 분해 박테리아들이 조사료 유입과 동시에 표면 부착이 발생하고, 이들 부착 섬유소 분해 박테리아의 활성화가 먼저 진행된 후에 섬유소 분해 활성화가 이루어져야 조사료 소화의 극대화를 가져올 수 있다는 사실을 제시하여 주었다.

• 한국수산과학회지
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• 제28권4호
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• pp.421-427
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• 1995

분흥성게의 양식군, 방류군, 야생군에 대하여 생식판에 나타나는 색소대를 연륜으로 하여, cluster 분석에 의한 지역별 성장 양상을 파악하고, 군집상호의 성장특성을 비교검토 하였다. 1. 단일연급군으로 구성된 양식군은 매년 9월 25일에서 10월 5일 사이에 출생한 개체들로서, 약 9-10개월후의 표본군에서는 $r_1$은 전혀 나타나지 않았고, 출생한지 1년 10-11개월의 표본군에서는 $r_1,$ 2년 9-10개월생에서는 $r_1$과 $r_2$가 형성되어있었으므로, $r_1$ 및 $r_2$의 윤문을 각각 연륜으로 취급하였다. 2. 양식군의 성장이 방류군 및 야생군보다 월등히 우수하였다. 또한 양식하는 개체군과 동일한 8-12mm의 어린성게를, 인접한 장소에 방류한 방류군은 자연산의 성장과 유사한 성장을 하였다. 3. 동일 연령에서 각장분포의 범위가 큰 것은 산란기가 긴 원인도 무시할 수 없지만, 양식군 및 야생군의 각 연급간의 overlap현상이 큰 것으로 보아 개체간의 성장 차가 큰 것 같다. 4. Yamaguchi, Cheju를 제외하고는 Kasiwazima에서 Nomozaki에 이르기까지 거리상으로 인접할수록 성장의 유사경향이 높다. 그리고, Cheju는 지리적으로 고립되어 있음에도 불구하고, 보다 가까운 Kasiwazima보다 Aba, Mogi 및 Toishi와 더욱 유사한 성장을 하였고, 위도상으로 가장 북쪽에 위치한 Yamaguchi가 가장 남쪽에 위치한 Nomozaki와 유사한 성장을 나타내고 있었다.

• 농약과학회지
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• 제14권2호
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• pp.123-132
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• 2010

국내 난방제 해충의 하나인 배추좀나방(Plutella xylostella)을 방제하기 위하여 사용되어온 상업용 Bacillus thuringiensis 제품들을 이용하여 국내 6개 지역에서 채집한 지역계통과 2개의 감수성계통 배추좀나방에 대한 저항성 발달정도를 검토하였다. 상품화된 B. thuringiensis subsp. kurstaki 계통인 Tyuneup$^{(R)}$, Thuricide$^{(R)}$, Geumulmang$^{(R)}$ 등 3제품과 B. thuringiensis subsp. aizawai 계통인 Tobagi$^{(R)}$, Scorpion$^{(R)}$ 등 2제품을 이용하였다. 공시충으로 사용된 배추좀나방은 계대사육중인 감수성개체군 NP와 GR 2종류이며, 전국의 배추밭에서 채집한 SP, HS, NM, DR, HC, HW개체군 등 6종류를 야외 개체군으로 사용하였다. Tyuneup$^{(R)}$ 제품의 생물검정에서 감수성 계통인 고령지시험장계통의 GR과 비교해 SP 개체군은 4.8배를 그리고 HS 개체군은 2.5배의 저항성발달을 보였다. Geumulmang$^{(R)}$ 제품의 경우에는 감수성계통인 NP 개체군에 비하여 SP 개체군에서 9.9배와 NM 개체군에서 6.8배정도의 저항성을 나타냈다. Tobagi$^{(R)}$는 HS 개체군에서 GR 개체군에 비해 14배의 저항성을 보여 가장 높게 나타났다. 그러나 동일 계통의 Scorpion$^{(R)}$은 SP 개체군에 약 2배정도의 저항성을 보여주고 있을 뿐이다. 이러한 결과는 어떤 특정한 B. thuringiensis 제품이 특정지역에 집중적으로 계속 사용함으로서 저항성이 발달되는 것으로 판단되며 종류가 다른 B. thuringiensis 제품을 교호 살포해야 할 것으로 사료된다. 그러나 Tobagi$^{(R)}$에 14배의 저항성 발달을 보인 HS 개체군을 실험실에서 동일약제에 연속으로 노출시켰을 때 $F_2$세대에서는 급격히 저항성 수치가 떨어져 1.1로 나타나 저항성 기작의 검토가 필요하다.

• 한국양식학회:학술대회논문집
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• 한국양식학회 2003년도 추계학술발표대회 논문요약집
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• pp.134-135
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• 2003

The geographic expansion of the toxic dinoflagellates genus Alexandrium has been shown to be world wide ranging. The members of the genus Alexandrium ocnstituted of 20-30 species did not show substantial differences in their morphology, which is mostly referred in the 'tamarensis species complex', except some species. Though rDNA sequences variations are very few and pseudogene types are so diverse that it is difficult to use them as the specific markers. In this study, we outlined Korean and Japanese A, tamarense and A. catenella regional isolates by phylogenetic analysis inferred from no cutting alignments of LSU rDNA D1-D2 and SSU rDNA sequences to group these regional isolates. The results were compared to RFLP patterns of PCR products targeted chloroplast DNA. Lastly screening of highly repeated microsatellite DNA which is frequently used for population analysis in eukaryotes was conducted. A. catenella regional strains identified by the sequencing of rDNA D1-D2 domain were divided into at least 3 groups of type E, CMC and Chinese type, divergence root may not be deep comparing with that of A. tamarense whose pseudogenes are very variable. Results of RFLP pattern and the phylogeny of the unknown gene targeting chloroplast showed that Korean and Japanese A. catenella regional isolates were divided into 3 types: Korean, Japanese and the third CMC types. Population-specific PCR amplification with Japanese A. catenella type-specific PCR primers was useful method for population analysis of A. catenella. Various types of satellite sequences such as 5 nucleotides repeats were obtained from A. tamarense and A. catenella. The 5 nucleotides repeats were primed at the both 3'and 5' ends, and these repeats were prominent as longer repeated motifs. This repeated DNA was intercalated as internal sequences containing various types subrepeats. It is expected that these satellite DNA would be a useful molecular population marker through detail comparison among Alexandrium regional isolates to trace their transferring pathway and to prevent their human-associated their regional extents.

• Animal Systematics, Evolution and Diversity
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• 제34권1호
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• pp.37-49
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• 2018

Two hypotrich ciliates, Australocirrus shii (Shi et al., 1997) Kumar & Foissner, 2015 and Afrokeronopsis aurea (Foissner & Stoeck, 2008) Foissner et al., 2010 isolated from freshwater habitats in Korea and were studied based on the specimens from live and after protargol impregnation. Australocirrus shii is redescribed based on morphology and 18S rRNA gene sequence, whereas Af. aurea is the first record for Korea. Main morphological features of the Korean population of Au. shii are as following: body size $100-200{\times}40-80{\mu}m$ in vivo; elongate to ellipsoidal or slightly elongate obovate, dorsoventrally flattened; transverse cirri arranged in (3+2) pattern, anterior pretransverse ventral cirrus distantly anterior of the first transverse cirrus; eight or nine dorsal kineties; and three caudal cirri. Main morphological features of the Korean population of Af. aurea are as following: body size $230-375{\times}70-145{\mu}m$ in vivo; shape elongate obovate or ellipsoidal, widest at the mid-body; undulating membranes in Australocirrus pattern with a buccal depression; and three caudal cirri. The Korean population of A. shii is similar in morphology with previous descriptions except for the presence of indentation at the posterior end in the Korean population. The Korean population of A. aurea is slightly shorter than the South African population and has slightly less marginal and mid-ventral cirri. The phylogenetic analysis of present two Korean hypotrichs and relevant species based on 18S rRNA gene sequences generated almost similar tree topologies compared with previous studies.

• Journal of Microbiology and Biotechnology
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• 제17권10호
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• pp.1645-1654
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• 2007

The total methylotrophic population associated with rice plants from different cultivars was enumerated at three different stages: vegetative, flowering, and harvesting. The bacterial population in the leaf, rhizosphere soil, endophytic in the stem and roots, and epiphytic in the florets and grains were determined from four rice cultivars, Il-mi, Nam-pyeoung, O-dae, and Dong-jin, sampled from three different field sites. The methylotrophic bacteria isolated on AMS media containing 0.5% methanol as the sole carbon source uniformly showed three distinct morphologies, which were recorded as separate groups and their distribution among the various samples was determined using the ecophysiological index. The growth stage at the time of sampling had a more significant effect on the methylotrophic population and their distribution than the field site or cultivar. A similar effect was also observed for the PPFMs, where their population in different plant parts increased from V10 to R4 and then decreased towards stage R9. A canonical discriminant analysis of the PPFM population from different parts of rice showed clear variations among the cultivars, sampled sites, and growth stages, although the variations were more prominent among the growth stages.